Expertise
in the emerging field of geoarchaeology led University of North Texas
scientist Reid Ferring to conclusions that are causing archaeologists
and anthropologists around the world to alter their perceptions of the
early history of the human species. As a member of an international research
team that unearthed two fossils in the Republic of Georgia in the summer
of 1999  an almost
complete skull and a separate skullcap 
the professor of archaeology, geology and physical geography played a
crucial role in dating this historic discovery. Ferring
and scientists from the Berkeley Geochronology Center determined that
the fossil skulls (found beneath a medieval ruin at Dmanisi in the southern
portion of the Republic of Georgia) are about 1.7 million years old. That
conclusion confirms that the Dmanisi fossils are the oldest human remains
found anywhere outside of Africa. Additionally, the scientists believe
that their find's distinct similarities to Homo
ergaster fossils (fossils dating back to the same time period
in Kenya and believed to be the African version of Homo
erectus) indicate that they have found the earliest known hominids
to migrate out of Africa. This indicates that members of the human species
left Africa hundreds of thousands of years earlier than scientists previously
thought.
In a May 12, 2000, Science
article, Ferring and his colleagues from the Republic of Georgia, France,
Germany and the United States described the find and discussed its significance.
Explaining his role in the discovery, Ferring was quoted on the international
wires of the Associated Press and Reuters, in newspapers from Dallas to
Istanbul, and on the air and Internet by CNN, MSNBC and the South Slavic
Service of Radio Free Europe.

An
early findThroughout
his career, Ferring, the current chair of UNT's Department of Geography,
has been excavating and examining human fossils and artifacts along with
any flora, fauna and physical features unique to the places they are discovered.
One of his aims is to formulate a more complete history of human evolution
and migration. As
a scientist with a special interest in the Pleistocene epoch (1.8 million
to 11,000 years ago) and doctoral degrees in both geology and anthropology,
Ferring combines his analyses of soil strata and sediments with his knowledge
of human fossils. He can determine if a fossil is from the same era as
the surrounding sediment or if the site has been disturbed.He
was recruited in 1993 to date the Dmanisi site and help settle disputes
over the age of an early human mandible that had been discovered there.
Some scientists believed the fossil to be more than 1 million years old,
while others held firmly to the theory that early humans did not migrate
from Africa into Eurasia and Europe until 500,000 years ago. Ferring says
problems in dating the jawbone were compounded by the facts that the site
had not yet been thoroughly dated and that the fossil's African connections
were unclear. Since his initial involvement, Ferring has devoted a portion
of each summer to work at the site. His research is funded by grants from
the Louis S.B. Leakey Foundation and the National Science Foundation.

Dating
methodsFerring
notes that because Dmanisi rests on a layer of volcanic rock, he was able
to use radioactive isotopic dating at the site. Radioactive isotopic dating
(in this case, potassium-argon radioactive dating) uses the phenomenon
of radioactive decay to determine the age of a sample.Lava
contains potassium, and over time the radioactive potassium decays into
argon gas, which is released into the atmosphere. In solid lava, argon
is trapped, so as time goes by the amount of argon in the rock increases.
Because the Earth contains relatively little argon and scientists know
the rate at which potassium decays into argon, they are able to determine
the age of a sample by its ratio of potassium to argon. Ferring
also used another method involving paleomagnetism, the permanent magnetism
found in rocks, to determine the site's age. He explains that iron-rich
crystals in rocks formed by cooling lava align with the Earth's magnetic
field. Matching that knowledge with knowledge of a magnetic shift about
1.78 million years ago, he was able to find evidence of the shift through
soil and sediment analysis. The deepest layers had normal magnetism, but
the poles of higher layers were reversed.By
combining both dating methods with the well-documented animal fossil record
of Dmanisi, Ferring and his colleagues set the age of the site at 1.7
million years.

Changed
perceptionsWhile
wrapping up the research on the site's age in 1999, members of the team
discovered the skull and skullcap in an area Ferring had long urged them
to explore. Given the age of the site and the fossils' distinct similarities
to the original African human species, the discoveries have altered previous
perceptions about human migration and now, according to Ferring, will
make Eurasia and Europe"fair
game" for a new round of archaeological digs. The
team has unearthed more than 2,000 identifiable vertebrate fossils and
more than 1,000 stone artifacts. Prior to this new find, scientists believed
that early humans left Africa only after they had created sophisticated
stone tools, but among the Dmanisi artifacts were simple tools similar
to the ones used in Africa more than 2 million years ago. Ferring speculates
that factors such as changes in social structure, physiology and ecology
played a more significant role in the African human migration than previously
imagined.With
the hopes of addressing the new questions raised by his recent findings,
Ferring returned to Dmanisi this August to continue his research. UNT
graduate student Johnny Byers of Fort Worth has also taken part in the
historic work.

Unearthing
the pastFerring
has another remarkable "oldest known" find to his credit 
this one in North Texas. He made a major archaeological discovery in 1988
at the U.S. Army Corps of Engineers Lake Ray Roberts construction site
near Aubrey. While out collecting fossils with his son, he discovered
an 11,500-year-old campsite that is the oldest known, best dated and best
preserved example of the Clovis people who populated the southern Plains
roughly 12,000 years ago.
In recent years, Ferring also has excavated
Paleolithic sites in Portugal to learn more about its Upper Pleistocene
prehistory.
His newest project is to work with the
Georgians to develop a five-year excavation plan. He hopes to continue
his work east of Dmanisi into the drier parts of Georgia and south into
Azerbaijan  as he
continues to unearth the history of human civilization from the dust of
the past.